This invention relates generally to circuit board interconnections, and particularly relates to a coupled circuit board configuration which provides adjoining board positioning flexibility together with structural integrity and electrical connection.
The rapidly increasing sophistication of electronic devices has been made possible by a number of technological advances. One area in which advances have led to enhanced electronics capabilities is that of device packaging and component layout. The component-dense circuit board and circuit board stacking arrangements have permitted the designer to incorporate more functions and more sophisticated operations per unit volume. Of course, thermal dissipation must be dealt with in these more densely packaged devices, but more efficient component design and materials in addition to increased micro-miniaturization have reduced the heat generated in this environment.
Circuit board layout and fabrication, including the placement of components and conductors thereon, is increasingly being accomplished by automated processes many of which are computer-controlled. Perhaps the greatest limitation on advances in this area has involved the interconnecting of individual circuit boards. This has resulted in the placing of restrictions on the circuit board designer and manufacturer in terms of relative board orientation to accommodate a unique environment or application, interconnecting board rigidity combined with large numbers of inter-board connectors, and high speed automated methods of manufacturing multi-board configurations with a minumum amount of material and expense. Finally, it is to be noted that interboard spacing and configuration plays another important role in terms of the access provided to board components and conductors. In many applications the problem of access to the circuit board module for purposes of replacement of parts or repair thereof is of paramount importance. Thus, increasingly flexible means for interconnecting circuit boards is a primary design goal.
One approach to the interconnecting of circuit boards is disclosed in U.S. Pat. No. 3,971,127 to Giguere in which is described a method for coupling two circuit boards involving the cutting of an aperture in a circuit board, the bridging of the aperture with a flexible circuit tape bonded to one side of the board, perforating holes through the board and the flexible tape, inserting the leads of electrical components through the holes and in a conductive relationship to the conductors on the flexible circuit tape, and folding the circuit board in the area of the aperture after the two edges of the board in the area of the aperture after the two edges of the board adjacent to the aperture are cut through. Thus, the two adjacent, coupled circuit boards are linked by means of a flexible conductive tape. While this configuration provides flexibility in relative board orientation, the coupling lacks rigidity and fails to provide mutual circuit board support if necessary. Another approach to circuit board coupling is described in U.S. Pat. No. 3,716,846 to Volckart, et al which involves the folding of the margin of a circuit board along a line of perforations. Input and output connectors symmetrically arranged across the fold line form electrically connected contacts on the front and rear of the folded circuit board. In this manner a dual sided circuit board edge connector surface is formed from a single sided structure and is aligned to be in electrical contact with similar structures mutually aligned and mechanically clamped together. This arrangement is intended not to provide flexibility in circuit board mounting but to provide improved board coupling between vertically stacked, mechanically clamped boards.
Other techniques and methods used in electrically and mechanically coupling circuit boards are disclosed in U.S. Pat. Nos. 3,221,286 to Fedde and 3,376,479 to Wines, et al. Both patents disclose means for connecting printed circuit boards but are limited in their application to a stacked assembly of circuit boards in which the boards are mounted in a generally parallel direction which is not capable of being varied to suit a particular environment or application. Still another approach to circuit board coupling is disclosed in U.S. Pat. No. 2,910,628 to Keener but this conductor panel assembly is limited to mechanically coupled circuit boards which are assembled in fixed right angular relation with respect to one another. Finally, U.S. Pat. No. 3,780,430 to Feeney involves the mounting of an electroluminescent display in a hand-held calculator above the level of the keyboard and at an angle to the keyboard making it more transverse to the line of sight of the viewer. More particularly, conductor pins mounted on the keyboard printed circuit board are bent relative to the plane of the keyboard circuit board prior to insertion on the circuit board of the display at a predetermined angle which optimizes user viewing of the electroluminescent display. Various relative circuit board angles are available, but once the conductor pins are bent to provide a particular configuration subsequent re-orientation of the display is not possible. In addition, the thin conductor pins provide only limited support for the electroluminescent display mounted on the keyboard.
The present invention is intended to avoid these circuit board mounting limitations by providing an inexpensive, machine compatible, circuit board mounting configuration which permits the circuit boards to be mounted at various relative angles in a semi-rigid construction in which the conductors linking the circuit boards provide substantial inter-board support.